Has anybody experimented with negative tail rocker? A polyethelene Surf Partner Dry [285] I used in the 80's warped. To be more precise the highly flexible skin, and chop pounding, crushed the poor quality foam in the tail part. The double concaves became so deep that they almost met the upper deck, and the tail bent slightly downwards. The incredible thing was it became incredibly fast, and dangerous! On a memorable offshore gale [flat water inshore] day, with a Vinta fully battened 5.5, it locked into a screaming close reach, which I didn't how the hell to get out of! [Locked in straps and harness, and frozen with fright.] I scrapped the ruddy thing - couldn't keep up with the cost of disinfectant for the wetsuit! I wonder, though,was the whole board just skimming the surface with only the negative rocker tail [and fin] in contact? Is it a valid concept for speed boards? ------[Sorry about lack of paragraphs. I can't work these computer thingy's properly yet.]